Should diesel primer stay hard?
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Should diesel primer stay hard?
Premium Member. The fuel system is in suck (vacuum) when running. Normal primer operation after shutdown or sitting is 2 to 3 pumps to get stiff. So, it should remain soft for up to 3 pumps on an operational truck.
How do you get air out of Duramax fuel lines?
Just crack the bleeder, turn on lift pump till solid fuel squirts out then close bleeder screw. If your fuel rail was empty or had air in it from R&R’ing injectors or CP3, you should give the plunger a few more pumps till it gets hard after closing the bleeder screw.
Where is the primer pump on a Duramax?
On the passenger side of the motor you will find the fuel filter assembly. On top there is a primer cylinder and a plastic bleeder screw. Pump the cylinder until it gets hard, then crack the bleeder and let the air out. Repeat the process until fuel comes out and the truck stays running.
What is the purpose of a diesel primer pump?
The purpose of the primer pump is to pump sufficient fuel from the supply tank to the engine and particularly to the injectors of a diesel engine to enable the engine to be cold-started without excessive use of the electrical system which normally operates the fuel pump.
Is there a fuel pump in the tank of a Duramax diesel?
The GMC and Chevy Duramax pick-up trucks do NOT have a lift pump to supply fuel to the engine. From the factory, the CP3 injection pump is the truck’s only means of getting fuel from the tank to the engine.
How often do CP4 pumps fail?
The Bosch CP4 fuel pump has an unusually high failure rate in the U.S., upwards of 7%, when compared to 1% failure rate in Europe.
Why is my primer ball not getting hard?
You might try running the hose and bulb to a can of gas (lots of things can go bad with can of gas, be careful) and see if the motor will fill and firm up the bulb. You can also remove the hose from motor and pump bulb, use your finger as a one way check valve. Once the bulb is full reconnect to the motor.
How does a fuel priming pump work?
In a priming application, where the fuel pump is only used during start up or when the fuel system has been drained completely of fuel, a priming pump is installed to prime the fuel system instantly and push fuel into the injection system. This allows the engine to start quickly and avoids unnecessary engine cranking.
